Long-term (12 to 18 months) functional voice assessment to detect voice alterations after thyroidectomy

Even when thyroidectomy preserves vocal cord motility it may leave patients with changes in voice quality. Although superior laryngeal nerve (LSN) damage after thyroidectomy manifests with aspecific symptoms, laryngoscopy discloses only slight morphological changes that are difficult to assess. We want to investigate the voice function in asymptomatic patients one year after thyroidectomy and to compare the obtained data against those of a healthy control group.

Thirty adult patients who had undergone thyroidectomy, all of them euphonic before and after the operation, were submitted to a complete voice assessment including voice self-evaluation tools, videolaryngostroboscopy and spectrographic analysis of voice. Primary outcome measures were differences between surgical patients and control group in terms of microperturbation of voice intensity and amplitude as measured by spectrographic analysis.

In patients who had undergone thyroidectomy, acoustic parameters indicating amplitude microperturbations resulted slightly altered. All these values exceeded normal MDVP thresholds. Another interesting finding in our study sample concerns the lower F0 values we recorded in women patients after surgery than in healthy controls. Voice alterations may reflect prelaryngeal muscle scarring or fibrosis. Consider the possible alterations of vocal quality caused by scarring after surgery therefore strongly recommend surgery when the situation allows it, not to dissect the prelaryngeal muscles but only to spread apart.

Our study conducted at least one year after thyroid surgery underlines that surgery-related slight voice deficits can persist over time. More refined phoniatric testing discloses voice alterations that normalize without specific rehabilitation therapy, therefore confirming that certain acoustic changes are clinically unimportant.